Internet domain owners can create a website for their domains and, if desired, impose a security overlay on the website. An example of such security is the Secure Sockets Layer (SSL). SSL defines a protocol by which the domain owner obtains a certificate from a trusted Certificate Authority (CA). The certificate is then used when a client of the website attempts to establish a connection to the website. The certificate may be accessed by the client's browser and used to confirm that the website is valid. Specifically, the client browser checks that the certificate has not expired, that the certificate was issued by a trusted CA, and that the certificate is being used by the website for which the certificate was issued. If the browser fails to verify any these checks, the browser may display a warning to the user of the client browser that the website is not secured by SSL. Otherwise, if all of these checks are passed, a visual indicator is provided in the client browser (e.g., a lock symbol) that the website is secure and can be trusted.
Generation of the SSL certificate is a multistep process that may be beyond the technical knowledge of many website owners. Further, SSL certificates are valid for a certain period of time that typically is fairly long. Certificate expiration dates one or two years into the future are commonplace. The website owner should renew the certificate before it expires, but given the certificate's long lifetime, it is easy for the renewal date to be forgotten by the website owner. If the certificate were to expire without being renewed, the website would no longer be protected by SSL and clients may not want to access unsecure websites.